compiling one program, not all, from a source package

[Donatas G.]

I need to recompile kwin to test some changes made upstream, that
would solve problems with my card. But kwin, or kde-window-manager
package and its additions have one large source package:
kde-workspace, that includes plasma-dekstop, systemsettings, ksysguard
and a lot of other programs. I can compile that whole bunch of
packages, but I do not really need all those, and it takes ages on my
aging machine.

How do I compile just the kde-window-manager related packages?

I did this so far:

apt-get source kde-window-manager  ## it is smart and downloads the
correct source packages
cd kde-workspace*
## I applied the patch and then:
dpkg-buildpackage -rfakeroot -uc -b

- that is still running, and if it finally ends in problems i will be
pulling my hair out...

So, is there any way to specify, which packages to build?

Donatas